Diagrammatic ab initio methods for infinite nuclear matter with modern chiral interactions

TL;DR

This paper compares three ab initio diagrammatic methods for calculating the equation of state of nuclear matter using modern chiral interactions, demonstrating their consistency and robustness in predicting nuclear properties.

Contribution

It provides a comprehensive benchmark of coupled-cluster, Green's functions, and perturbation theory methods with chiral potentials, highlighting their agreement and reliability.

Findings

Highly precise results for pure neutron matter.

Robust predictions for symmetric nuclear matter.

Consistency across different many-body methods.

Abstract

A comparative study of the equation of state for pure neutron matter and symmetric nuclear matter is presented using three ab initio methods based on diagrammatic expansions: coupled-cluster theory, self-consistent Green's functions, and many-body perturbation theory. We critically evaluate these methods by employing different chiral potentials at next-to-next-to-leading-order -- all of which include both two- and three-nucleon contributions -- and by exploring various many-body truncations. Our investigation yields highly precise results for pure neutron matter and robust predictions for symmetric nuclear matter, particularly with soft interactions. Moreover, the new calculations demonstrate that the $\rm{ NNLO_{sat} }(450)$ and $\Delta \rm{NNLO_{go}}(394)$ potentials are consistent with the empirical constraints on the saturation point of symmetric nuclear matter. Additionally, this benchmark study reveals that diagrammatic expansions with similar architectures lead to consistent many-body correlations, even when applied across different methods. This consistency underscores the robustness of the diagrammatic approach in capturing the essential physics of nucleonic systems.